U.S. Pat. No. 5,912,244 (“the '244 patent”) discloses the compound 6-[[(3S,4R)-3,4-dihydro-3-hydroxy-6-[(3-hydroxyphenyl)sulfonyl]-2,2,3-trimethyl-2H-1-benzopyran-4-yl]oxy]-2-methyl-3(2H)-pyridazinone (hereinafter “the Compound”), methods for its preparation and its use as a potassium channel opener. The '244 discloses that potassium channel openers may be used to treat diseases associated with altered tone or motility of smooth muscles. Examples of such conditions include chronic obstructive airway disease, asthma, urinary incontinence, hypertension, myocardial ischemia, cerebral ischemia, and glaucoma.
Example 7 of the '244 patent illustrates the preparation of the Compound, as the ethanol solvate. The ethanol solvate converts to an amorphous form over time. New crystalline forms of the Compound, having enhanced crystalline stability, would be an improvement over the prior art. Such forms would be more amenable to handling and formulating into finished dosage forms at clinical or industrial scale.
Copending, commonly assigned, U.S. patent application Ser. No. 60/544,116 (the '116 application) discloses the use of the Compound to promote hair growth in mammals. The '116 application discloses that the Compound stimulates the growth of the hair follicle, increases the number of follicles in the anagen phase and increases the period of time that follicles remain in the anagen phase (i.e., increases the anagen to telogen ratio).